The Essential Program on Immunization is 50: Milestones, achievements, and future directions

By Antonia Du Bois, MScReviewed by Lily Ramsey, LLM

Overview of the Essential Program on Immunization
Key milestones and achievements over 50 years
Challenges faced and overcome
EPI and the COVID-19 pandemic
The future of immunization: Innovations and strategies
Celebrating 50 years of immunization: A look forward
References
Further reading

Each year, the World Health Organization (WHO) partakes in World Immunization Week, a period of reflection, raising awareness, and future planning surrounding global action required to combat vaccine-preventable illness.¹

This year marks the 50th anniversary of the Essential Programme on Immunization (EPI), a WHO program focused on equity in childhood vaccine access.^1,2

Overview of the Essential Program on Immunization

Launched in 1974 by the WHO, the EPI’s primary objective is to establish equal access to life-saving vaccination in children across all geographical locations and socioeconomic statuses.^1-4 This continually evolving initiative has resulted in more children provided with immunization access than any recorded time in history and the presence of a national immunization program in every country.^2,5,6

The EPI began with a moderate portfolio of vaccinations for six childhood illnesses including diphtheria, tetanus, and pertussis.^2,3 Building on fundamentals of health systems like governance, service delivery, information systems, vaccine formulation, and financing,⁵ this program has expanded to a total of thirteen vaccinations and includes older children and adults.^2,3

Read More World Immunization Week Content

Key milestones and achievements over 50 years

The past 50 years have seen many achievements in the vaccination sphere worth celebrating during World Immunization Week, beginning with the impressive success of the smallpox eradication program most active from 1966-1977.^2,6 The innovations of this success story formed the foundation for the EPI and mark one of the greatest achievements in immunization history.^2,6

On track to be the next major eradication success is that of polio.^2,4 This is in part due to the collaboration of the WHO with the US Centres for Disease Control (CDC), UNICEF, and The Vaccine Alliance, but also due to responses from individual countries.² For example, the polio eradication program established in Nigeria was so successful that it helped inform a swift and effective response to a future outbreak of ebola.⁴ The cumulation of these efforts resulted in a reduction in polio infections by over 99%.²

In addition to polio, the EPI has demonstrated a notable positive impact on other diseases such as hepatitis B and diphtheria.^6,7 In Malaysia, an effort to expand HBV vaccination in schoolchildren saw a vaccination rate of 93.7% directly under the EPI.⁷ Similar success was seen in the distribution of the DTP3 diphtheria vaccine, with coverage rising from 20% in 1980 to over 85% confirmed coverage in 2010.⁶

Challenges faced and overcome

One of the primary challenges with large-scale immunization programs is the requirement for sustained long-term investment.⁵ Previous initiatives have run into problems with prioritizing increasing coverage over establishing sustainable healthcare systems.⁵ This can result in the diversion of funding and the masking of low local coverage rates, negatively affecting the overall program progress.⁵

This can be quantified in coverage stagnation throughout the 1990s, particularly in regions of Africa.⁵ More recently, national surveillance in Pakistan overestimated vaccine coverage by missing reporting of delayed vaccination in young children.⁸

An additional challenge is that the WHO does not set policies for individual countries within large-scale vaccination programs.⁵ Those governing bodies must establish their own policies and guidelines which can lead to disharmony in the standards and expectations from country to country.⁵

To address this disharmony, the past ten years have seen sustained efforts to establish coordinated organizations such as National Immunization Technical Advisory Groups (NITAGs) and Interagency coordinating committees to improve stakeholder communication and resource distribution.⁵

Image Credit: Studio Romantic/Shutterstock.com

EPI and the COVID-19 pandemic

The unprecedented nature of the SARS-CoV-2 pandemic required a coordinated, swift, and effective immunization response at a global level with the EPI playing a significant role. Faced with one of the most challenging global vaccine initiatives in history, the EPI helped implement vaccination in nearly every country within only 18 months.⁹

While impressive, the significant cost of such an effort to the healthcare systems of many countries and jurisdictions has created a situation in need of constant improvement. The EPI set out to do just that with published plans and recommendations for the global implementation of COVID-19 vaccination into standard immunization programs in an equity- and people-focused approach.⁹

As outlined in a WHO publication in 2022, their plans for integrating COVID-19 vaccination into routine immunization have the advantages of reducing missed vaccinations and aiding in lessening strain on healthcare systems.⁹ These approaches can also present logistical challenges with outreach to different target groups and supply chain logistics for different vaccines and commodities.⁹

The future of immunization: Innovations and strategies

The past 50 years of EPI operations have established that a faulty health system can cripple the benefits of even the best vaccine. As seen in the aforementioned coverage dips in the 1990s, addressing vaccine access inequities and strengthening the foundation of healthcare systems is essential for the continued success of the EPI.⁵

During a meeting of the Immunization and Vaccine-Related Implementation Research Advisory Committee (IVIR-AC) in September of 2023, the WHO outlined ongoing campaigns and approaches, including measles elimination, HPV vaccination, and modelling-informed policy implementation.¹⁰ This continued work, paired with the people-first approach outlined in the COVID-19 immunization integration plan, the EPI is set out to continue influential work that saves millions of lives around the globe.^9,10

Celebrating 50 years of immunization: A look forward

The arrival of the EPI’s 50th anniversary marks a pivotal moment to reflect on some of the greatest recorded triumphs in public health and immunization. The work of the EPI over these decades has transformed the global landscape of public health and is poised to continue this upward trend.

As discussed in previous paragraphs and evidenced by the swift COVID-19 immunization response, global cooperation and collaboration are essential for equitable and effective vaccine access. Organizations such as the EPI will hopefully continue to play a pivotal role in such efforts for another 50 years to come.

References

1. World Immunization Week 2024. World Health Organization. Accessed March 25, 2024. https://www.who.int/campaigns/world-immunization-week/2024
2. 50th Anniversary of the Expanded Programme on Immunization (EPI). World Health Organization. Accessed March 25, 2024. https://www.who.int/news-room/events/detail/2024/01/01/default-calendar/50th-anniversary-of-the-expanded-programme-on-immunization-(epi)
3. Essential Programme on Immunization. World Health Organization. Accessed March 25, 2024. https://www.who.int/teams/immunization-vaccines-and-biologicals/essential-programme-on-immunization#:~:text=The%20Essential%20Programme%20on%20Immunization,populations%20across%20the%20life%20course.
4. Sodha SV and Dietz V. Strengthening routine immunization systems to improve global vaccination coverage. British Medical Bulletin. 2015;113(1):5-14. doi:10.1093/bmb/ldv001
5. Shen AK, Fields R, McQuestion M. The future of routine immunization in the developing world: challenges and opportunities. Global Health: Science and Practice. 2014;2(4):381-394. doi:10.9745/GHSP-D-14-00137
6. Okwo-Bele JM, Cherian T. The expanded programme on immunization: A lasting legacy of smallpox eradication. Vaccine. 2011;29:D74-D79. doi:10.1016/j.vaccine.2012.01.080
7. Ng KP, Saw TL, Baki A, et al. Impact of the Expanded Program of Immunization against hepatitis B infection in school children in Malaysia. Medical Microbiology and Immunology. 2005;194(3):163-168. doi:10.1007/s00430-004-0231-4
8. Qazi U, Malik S, Raza UA, et al. Compliance to timely vaccination in an Expanded Program on Immunization center of Pakistan. Vaccine. 2019;37(32):4618-4622. doi:10.1016/j.vaccine.2018.01.044
9. World Health Organization, Immunization, Vaccines and Biologicals (IVB). Considerations for integrating COVID-19 vaccination into immunization programmes and primary health care for 2022 and beyond. 2022. https://www.who.int/publications/i/item/9789240064454
10. World Health Organization, Immunization and vaccines related implementation research advisory committee, Immunization, Vaccines and Biologicals (IVB). Weekly Epidemiological Record Meeting of the Immunization and Vaccine-related Implementation Research Advisory Committee (IVIR-AC), September 2023. 2024;9(99):11-22. https://www.who.int/publications/i/item/who-wer9903-11-22

Further reading

• Immunization strategies: What lessons can we learn from successful campaigns?
• What is the Importance of Vaccination Coverage?
• World Health Day: Celebrating 75 Years of the WHO